Low-dose cytarabine to prevent myeloid leukemia in children with Down syndrome: TMD Prevention 2007 study.

Approximately 5% to 10% of children with Down syndrome (DS) are diagnosed with transient myeloproliferative disorder (TMD). Approximately 20% of these patients die within 6 months (early death), and another 20% to 30% progress to myeloid leukemia (ML-DS) within their first 4 years of life. The aim of the multicenter, nonrandomized, historically controlled TMD Prevention 2007 trial was to evaluate the impact of low-dose cytarabine treatment on survival and prevention of ML-DS in patients with TMD. Patients received cytarabine (1.5 mg/kg for 7 days) in case of TMD-related symptoms at diagnosis (high white blood cell count, ascites, liver dysfunction, hydrops fetalis) or detection of minimal residual disease (MRD) 8 weeks after diagnosis. The 5-year probability of event-free and overall survival of 102 enrolled TMD patients was 72 ± 5% and 91 ± 3%, respectively. In patients eligible for treatment because of symptoms (n = 43), we observed a significantly lower cumulative incidence (CI) of early death as compared with symptomatic patients in the historical control (n = 45) (12 ± 5% vs 33 ± 7%, = .02). None of the asymptomatic patients in the current study suffered early death. However, the treatment of symptomatic or MRD-positive patients did not result in a significantly lower CI of ML-DS (25 ± 7% [treated] vs 14 ± 7% [untreated], = .34 [per protocol analysis]; historical control: 22 ± 4%, = .55). Thus, low-dose cytarabine treatment helped to reduce TMD-related mortality when compared with the historical control but was insufficient to prevent progression to ML-DS. This trial was registered at EudraCT as #2006-002962-20.